1. Field of the Invention
The instant invention relates to thoracic catheters and more specifically to a device for connecting thoracic catheters to a source of suction such as a chest drainage unit or the like.
2. Background of the Invention
Thoracic catheters are often used to remove liquids and air from the thoracic cavity as a result of surgery or injury to the thoracic cavity. A typical prior art thoracic catheter, shown in FIG. 1, is an elongated tube with a distal end 2 and a proximal end 3. The distal end 2 of the catheter is placed in the thoracic cavity and contains several openings 4 to allow the fluids in the thoracic cavity to pass into the lumen of the tube. The proximal end 3 of the catheter is connected to a source of vacuum pressure (not shown) through a CDU connector A on a device such as a chest drainage unit.
A problem with thoracic catheters, especially catheters of small diameters, has been that it is very difficult to attach the proximal end 3 of the catheter to the CDU connector A on a chest drainage unit. In the case of thoracic catheters of small diameter, this difficulty results primarily from the fact that the CDU connector A on a chest drainage unit is relatively large compared to the inside diameter of the thoracic catheter. As a result, the small diameter catheter must be stretched to fit onto the connector on the chest drainage unit. This is often a difficult procedure.
Consequently, as shown in FIG. 2, a "funnel" 5 having a larger inside diameter than the inside diameter of the proximal end 3 of thoracic catheter tube 1 is sometimes attached to the proximal end 3 of the thoracic catheter to facilitate connecting the proximal end 3 of the catheter to the CDU connector A of the chest drainage unit. However, a consequence of the funnel 5 having a larger inside diameter than the thoracic catheter is that it also has a larger outside diameter than the proximal end 3 of the catheter tube 1.
In most uses of catheters with or without "funnel" ends, the proximal end 3 of the thoracic catheter is inserted through an opening in the intercostal space between a patient's ribs from the inside of the patient's thoracic cavity to the outside. With catheters having a "funnel" end, the comparatively larger outside diameter of the funnel 5 requires a larger opening to be cut in the intercostal space than is required for catheters not having the "funnel" end. Consequently, in the case of catheters with "funnel" ends, the "funnel" which makes it easier to attach the catheter to the CDU connector of a chest drainage unit, makes it necessary to make a larger than usual cut in a patient's intercostal space in order to pass the "funnel" end through the cut.
Of course it is desirable to minimize the size of the hole cut in the intercostal wall and also to make it as easy as possible to move the catheter through the opening. Because of the size of the "funnel" end, it is desirable to make the hole in the intercostal space as small as possible and still allow the "funnel" end to pass through. The tendency to make the hole as small as possible makes it more difficult to move the catheters with the "funnel" tips through the small opening once cut.
These problems with funnel end thoracic catheters are particularly magnified in the case of pediatric patients where the size of the opening in the intercostal wall to allow the "funnel" to pass through is relatively large in comparison with the available space between the ribs in the mature adult patient.
In addition, small diameter thoracic catheters are also more likely to be used in pediatric cases. As stated above, the small diameter catheters without the "funnel" end are difficult to attach to the connector A of a chest drainage unit.